There is no mentioning of changes to pessimistic locking in Mendix’ release notes. Only two mentions here in 7.23 and here in 8.1of solving ticket 85222 concerning optimisic locking: “We fixed an issue that prevented sessions from staying alive when using optimistic locking. (Ticket 85222)”

I just wanted to let people know that we have a new version of the Pessimistic Locking marketplace module  in development which will also work for offline-first native mobile (currently in 9.24).  I'm just in the process of testing it thoroughly. Please feel free to contact me if you are interested.

I have just published the updated version of Pessimistic Locking.  It is published in 9.24 but should be easily updatable to Mx 10.  It now supports Native Mobile alongside web.